Mark pattern in semiconductor device

ABSTRACT

A mark pattern includes unit cells immediately adjacent to each other and arranged in a form of dot matrix to form a register mark or an identification code, wherein each unit cell has configuration identical to functional devices of pMOS and nMOS, and each unit cell includes a first active region, a second active region isolated from the first active region, and first gate structures extending along a first direction and are arranged along a second direction perpendicular to the first direction, and the first gate structures straddling the first active region and the second active region, contact structures disposed between the first gate structures on the first active region and the second active region, and via structures disposed on the contact structures and two opposite ends of the first gate structures.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of application Ser. No. 15/347,757, filed on Nov. 9, 2016 and entitled “SEMICONDUCTOR DEVICE”, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a mark pattern, and more particularly, to a mark pattern in a scribe line of a semiconductor device.

2. Description of the Prior Art

Nowadays, integrated circuits (ICs) are used almost everywhere. However, the process of fabricating integrated circuits is complicated and involves four major stages: IC designs, wafer fabrication, wafer testing and wafer packaging. The total number of steps for fabricating an IC chip frequently exceeds a few hundreds.

The fabrication of integrated circuit devices can be roughly divided into three major stages, namely, silicon chip fabrication, integrated circuit fabrication and integrated circuit device packaging. In the integrated circuit fabrication stage, a number of patterns such as alignment marks, monitoring and/or measuring patterns, electrical testing patterns and product codes are formed on wafer scribe lines. Thereafter, the wafer is sawn to produce individual chip ready for carrying out the complicated integrated circuit packaging process.

Typically, the mark pattern is an intact pattern formed by one material layer occupying a large area. That is, a pattern density in the scribe line is much lower than a pattern density in the chip area. Loading effect is therefore caused by the density difference therebetween. As a result, etching rate in the chip area is made lower than that in the scribe line. In other words, loading effect adversely affects at least the reliability of the semiconductor IC fabrication. Furthermore, the conventional mark pattern is respectively formed in one layer, it is found that the mark pattern therefore fails the layer-to-layer integration consideration.

In view of the above, there exists a need for providing a mark pattern that mitigates loading effect and improves the layer-to-layer integration.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a mark pattern in a semiconductor device is provided. The mark pattern includes a plurality of unit cells immediately adjacent to each other and arranged in a form of dot matrix to form a register mark or an identification code, wherein each unit cell has configuration identical to functional devices of pMOS and nMOS, and wherein each unit cell includes a first active region, a second active region isolated from the first active region, wherein a conductivity type of the first active region is complementary to a conductivity type of the second active region, a plurality of first gate structures extending along a first direction and arranged along a second direction perpendicular to the first direction, and the first gate structures straddling the first active region and the second active region, a plurality of contact structures disposed between the first gate structures on the first active region and the second active region, and a plurality of via structures disposed on the contact structures and two opposite ends of the first gate structures.

According to the mark pattern provided by the present invention, the mark pattern formed in the scribe line is constructed by the plurality of unit cells, and each unit cells includes configurations identical to the devices formed in the chip areas. Therefore, pattern densities in the scribe line and the chip areas are made the same, and thus loading effect is mitigated. Furthermore, since the unit cells respectively include elements formed in different layers, it is concluded that at least those layers are involved for constructing the unit cells. Thus layer-to-layer integration is easily achieved.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are schematic drawings respectively illustrating a semiconductor device including a mark pattern provided by embodiments of the present invention.

FIG. 3 is an enlarged view taken from FIGS. 1 and 2 and is a schematic drawing illustrating unit cells for forming the mark pattern provided by a first preferred embodiment.

FIG. 4 is a schematic drawing illustrating a modification to the first preferred embodiment provided by the present invention.

FIG. 5 is a schematic drawing illustrating another modification to the first preferred embodiment provided by the present invention.

FIG. 6 is an enlarged view taken from FIGS. 1 and 2 and is a schematic drawing illustrating unit cells for forming the mark pattern provided by a second preferred embodiment.

FIG. 7 is a schematic drawing illustrating a modification to the second preferred embodiment provided by the present invention.

FIG. 8 is a schematic drawing illustrating another modification to the second preferred embodiment provided by the present invention.

FIG. 9 is an enlarged view taken from FIGS. 1 and 2 and is a schematic drawing illustrating unit cells for forming the mark pattern provided by a third preferred embodiment.

FIG. 10 is a schematic drawing illustrating a modification to the third preferred embodiment provided by the present invention.

FIG. 11 is a schematic drawing illustrating another modification to the third preferred embodiment provided by the present invention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth, such as particular structures, components, materials, dimensions, processing steps and techniques, in order to provide a thorough understanding of the present invention. However, it will be appreciated by one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known structures or processing steps have been described in detail in order to avoid obscuring the invention.

It will be understood that when an element is referred to as being “formed” on another element, it can be directly or indirectly, formed on the given element by growth, deposition, etch, attach, connect, or couple. And it will be understood that when an elements or a layer is referred to as being “on”, “connected to”, or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer and/or section from another. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, “in”, “on” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device in the figures in turned over, elements described as “below” or “beneath” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the inventions. As used herein, the singular form “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Please refer to FIGS. 1 and 2, which are schematic drawings respectively illustrating a semiconductor device including a mark pattern provided by embodiments of the present invention. As shown in FIGS. 1 and 2, the embodiment provides a semiconductor device 100, and the semiconductor device 100 includes a substrate 102. A plurality of chip area 104 and a scribe line 106 are defined on the substrate 102. In accordance with the preferred embodiment, various devices such as, for example but not limited to metal-oxide-semiconductor (MOS) transistor device (not shown), for constructing integrated circuits are formed in the chip areas 104. Those skilled in the art would easily realize that the substrate 102 can include many other active and passive devices (not shown) fabricated therein and/or thereon by front-end-of-line (FEOL) process. More important, a plurality of unit cells 110 u/110 u/110 u″ are formed in the scribe line 106 as shown in FIGS. 1 and 2. The unit cells 110 u/110 u′/110 u″ are formed by steps for forming the devices in the chip areas 104, therefore the unit cells 110 u/110 u/110 u″ include constructing elements with materials and spatial relationship the same with those in the chip areas 104. More important, the unit cells 110 u/110 u′/110 u″ are arranged to form a mark pattern 110 in the scribe line 106 as shown in FIGS. 1 and 2. In other words, the mark pattern 110 provided by the preferred embodiments of the present invention includes a plurality of unit cells 110 u/110 u′/110 u″.

It is well-known to those skilled in the art that mark pattern 110 can be, for example, a register mark pattern for lithography, an alignment mark, a monitoring and/or measuring pattern, an electrical testing pattern or a product identification (ID) code, thus the unit cells 110 u/110 u′/110 u″ can be arranged to forma register patterns for lithography as shown in FIG. 1, but not limited to this. Or, the unit cells 110 u can be arranged to form a product ID code as shown in FIG. 1, but not limited to this. More important, the unit cells 110 u/110 u′/110 u″ are immediately adjacent to each other to form the mark pattern 110.

Please refer to FIG. 3, which is an enlarged view taken from FIGS. 1 and 2 and is a schematic drawing illustrating unit cells for forming the mark pattern provided by a first preferred embodiment. As shown in FIG. 3, each of the unit cells 110 u includes a first active region 112 p and a second active region 112 n isolated from the first active region 112 p. As mentioned afore, the first active region 112 p and the second active region 112 n can be formed by steps performed to the chip areas 104, therefore the first active region 112 p includes a first conductivity type, the second active region 112 n include a second conductivity type, and the first conductivity type and the second conductivity type are complementary to each other. In the preferred embodiment, the first conductivity type is a p type and the second conductivity type is an n type, but not limited to this. The unit cell 110 u further includes a plurality of first gate structures 120 extending along a first direction D1 and arranged along a second direction D2 perpendicular to the first direction D1 within a substrate-horizontal plane. As shown in FIG. 3, the first gate structures 120 straddle the first active region 112 p and the second active region 112 n. The unit cell 110 u further includes a plurality of first conductive structures 130, and the first conductive structures 130 are disposed on the first active region 112 p, the second active region 112 n, and two opposite ends of the first gate structures 120 as shown in FIG. 3. According to the preferred embodiment, each of the unit cells 110 u further includes a plurality of second conductive structures 132 extending along the first direction D1 and the straddling the first active region 112 p and the second active region 112 n. And portions of the first conductive structures 130 are disposed on the second conductive structures 132, as shown in FIG. 3. Specifically speaking, the second conductive structures 132 are formed in between the first conductive structures 130 and the first active region 112 p, and also in between the first conductive structures 130 and the second active region 112 n within a substrate-thickness plane.

As mentioned above, the constructing elements of the unit cells 110 u, such as the first gate structures 120, the first conductive structures 130 and the second conductive structures 132, can be formed by the same steps performed to the chip areas 104. In other words, the first gate structures 120 can be formed simultaneously with forming the gate structures (not shown) in the chip areas 104. In the same concept, the second conductive structures 132 can be formed simultaneously with forming contact and/or slot contact (not shown) in the chip areas 104, and the first conductive structures 130 can be formed simultaneously with forming via structures (not shown) in the chip areas 104. Therefore, the pattern densities in the scribe line 106 and the chip areas 104 are similar.

Please refer to FIG. 4, which is a schematic drawing illustrating a modification to the first preferred embodiment provided by the present invention. According to the modification, each of the unit cells 110 u further includes a pair of first wiring layers 140 extending along the second direction D2. And the pair of first wiring layers 140 are respectively formed at the two opposite ends of each first gate structure 120. According to the modification, the first wiring layers 140 on the same side in different unit cells 110 u arranged in a same row are connected to each other as shown in FIG. 4. However, those skilled in art would easily realize that the first wiring layers 140 in different unit cells 110 u in the same row can be physically spaced apart from each other if required. As mentioned above, the pair of the first wiring layers 140 can be formed simultaneously with forming a wiring layer (not shown), such as a first metal wiring layer (M1) of an interconnection structure (not shown) in the chip areas 104. Therefore, the wiring pattern densities in the scribe line 106 and the chip areas 104 are similar.

Please refer to FIG. 5, which is a schematic drawing illustrating another modification to the first preferred embodiment provided by the present invention. According to the modification, each of the unit cells 110 u further includes a plurality of second wiring layers 142 extending along the second direction D2. According to the modification, the second wiring layers 142 in different unit cells 110 u in the same row are connected to each other as shown in FIG. 5. However, those skilled in art would easily realize that the second wiring layers 142 in different unit cells 110 u in the same row can be physically spaced apart from each other if required. As mentioned above, the second wiring layers 140 can be formed simultaneously with forming a wiring layer (not shown), such as a second metal wiring layer (M2) of the interconnection structure (not shown) in the chip areas 104. Therefore, the wiring pattern densities in the scribe line 106 and the chip areas 104 are similar.

According to the semiconductor device 100 provided by the present invention, the mark pattern 110 formed in the scribe line 106 is constructed by the plurality of unit cells 110 u, and each unit cell 110 u includes configurations identical to the devices such as pMOS and nMOS formed in the chip areas 104. Therefore, pattern densities in the scribe line 106 and the chip areas 104 are made the same, and thus loading effect is mitigated. Furthermore, since the unit cells 110 u respectively include elements formed in different layers such as the layer of the first gate structures 120, the layer of the second conductive structures 132, the layer of the first conductive structures 130, the layer of the first wiring layers 140, and the layer of the second wiring layers 142, it is concluded that at least those layers are involved for constructing the unit cells 110 u. Thus layer-to-layer integration is easily achieved.

Please refer to FIG. 6, which is an enlarged view taken from FIGS. 1 and 2 and is a schematic drawing illustrating unit cells for forming the mark pattern provided by a second preferred embodiment. As shown in FIG. 6, each of the unit cells 110 u′ includes a first active region 112 p, a second active region 112 n, a third active region 114 p and a fourth active region 114 n. And the first active region 112 p, the second active region 112 n, the third active region 114 p and the fourth active region 114 n are isolated from each other. As mentioned afore, those active regions 112 p, 112 n, 114 p, and 114 n can be formed by steps performed to the chip areas 104, therefore the first active region 112 p and the third active region 114 p include a first conductivity type, the second active region 112 n and the fourth active region 114 n include a second conductivity type, and the first conductivity type and the second conductivity type are complementary to each other. In the preferred embodiment, the first conductivity type is a p type and the second conductivity type is an n type, but not limited to this. More important, the first active region 112 p and the third active region 114 p are arranged along a second direction D2, and the second active region 112 n and the fourth active region 114 n are also arranged along the second direction D2. The unit cell 110 u′ further includes a plurality of first gate structures 120 arranged along the second direction D2 and extended along a first direction D1 perpendicular to the second direction D2 within a substrate-horizontal plane. As shown in FIG. 6, the first gate structures 120 straddle the first active region 112 p and the second active region 112 n, and also straddle the third active region 114 p and the fourth active region 114 n. In the preferred embodiment of the present invention, the unit cell 110 u′ can further include a pair of dummy gate structures 120 d disposed at two opposite sides along the second direction D2. The unit cell 110 u′ further includes a plurality of first conductive structures 130. As shown in FIG. 6, the first conductive structures 130 are disposed on the first active region 112 p, the second active region 112 n, the third active region 114 p, the fourth active region 114 n and two opposite ends of the first gate structures 120. According to the preferred embodiment, each of the unit cells 110 u′ further includes a plurality of second conductive structures 132 extending along the first direction D1 and arranged along the second direction D2. Furthermore, the second conductive structures 132 straddle the first active region 112 p and the second active region 112 n, and straddle the third active region 114 p and the fourth active region 114 n. As shown in FIG. 6, portions of the first conductive structures 130 are disposed on the second conductive structures 132. Specifically speaking, the second conductive structures 132 are formed in between the first conductive structures 130 and the active regions 112 p/112 n/114 p/114 n within a substrate-thickness plane.

As mentioned above, the constructing elements of the unit cells 110 u′, such as the first gate structures 120, the first conductive structures 130 and the second conductive structures 132, can be formed by the same steps performed to the chip areas 104. In other words, the first gate structures 120 can be formed simultaneously with forming the gate structures (not shown) in the chip areas 104. In the same concept, the second conductive structures 132 can be formed simultaneously with forming contact and/or slot contact (not shown) in the chip areas 104, and the first conductive structures 130 can be formed simultaneously with forming via structures (not shown) in the chip areas 104. Therefore, the pattern densities in the scribe line 106 and the chip areas 104 are similar.

Please refer to FIG. 7, which is a schematic drawing illustrating a modification to the second preferred embodiment provided by the present invention. According to the modification, each of the unit cells 110 u′ further includes a pair of first wiring layers 140 extending along the second direction D2. And the pair of first wiring layers 140 are respectively formed at the two opposite ends of portions of the first gate structures 120. According to the modification, the first wiring layers 140 on the same side in different unit cells 110 u arranged in a same row are spaced apart from each other as shown in FIG. 7, but not limited to this. As mentioned above, the pair of the first wiring layers 140 can be formed simultaneously with forming a wiring layer (not shown), such as a first metal wiring layer (M1) of an interconnection structure (not shown) in the chip areas 104. Therefore, the wiring pattern densities in the scribe line 106 and the chip areas 104 are similar.

Please refer to FIG. 8, which is a schematic drawing illustrating another modification to the second preferred embodiment provided by the present invention. According to the modification, each of the unit cells 110 u′ further includes a plurality of second wiring layers 142 extending along the second direction D2. According to the modification, the second wiring layers 142 in different unit cells 110 u′ in the same row are connected to each other as shown in FIG. 8. However, those skilled in art would easily realize that the second wiring layers 142 in different unit cells 110 u′ in the same row can be physically spaced apart from each other if required. As mentioned above, the second wiring layers 140 can be formed simultaneously with forming a wiring layer (not shown), such as a second metal wiring layer (M2) of the interconnection structure (not shown) in the chip areas 104. Therefore, the wiring pattern densities in the scribe line 106 and the chip areas 104 are similar.

According to the semiconductor device 100 provided by the present invention, the mark pattern 110 formed in the scribe line 106 is constructed by the plurality of unit cells 110 u′, and each unit cell 110 u′ includes configurations identical to the devices such as inverters formed in the chip areas 104. Therefore, pattern densities in the scribe line 106 and the chip areas 104 are made the same, and thus loading effect is mitigated. Furthermore, since the unit cells respectively include elements formed in different layers such as the layer of the first gate structures 120, the layer of the second conductive structures 132, the layer of the first conductive structures 130, the layer of the first wiring layers 140, and the layer of the second wiring layers 142, it is concluded that at least those layers are involved for constructing the unit cells 110 u′. Thus layer-to-layer integration is easily achieved.

Please refer to FIG. 9, which is an enlarged view taken from FIGS. 1 and 2 and is a schematic drawing illustrating unit cells for forming the mark pattern provided by a third preferred embodiment. As shown in FIG. 9, each of the unit cells 110 u″ includes a first active region 112 p, a second active region 112 n, a third active region 114 p, a fourth active region 114 n, a fifth active region 116 p and a sixth active region 116 n. And the first active region 112 p, the second active region 112 n, the third active region 114 p, the fourth active region 114 n, the fifth active region 116 p and the sixth active region 116 n are isolated from each other. As mentioned afore, those active regions 112 p, 112 n, 114 p, 114 n, 116 p and 116 n can be formed by steps performed to the chip areas 104, therefore the first active region 112 p, the third active region 114 p and the fifth active region 116 p include a first conductivity type, the second active region 112 n, the fourth active region 114 n and the sixth active region 116 n include a second conductivity type, and the first conductivity type and the second conductivity type are complementary to each other. In the preferred embodiment, the first conductivity type is a p type and the second conductivity type is an n type, but not limited to this. More important, the first active region 112 p, the third active region 114 p and the fifth active region 116 p are arranged along a second direction D2, and the second active region 112 n, the fourth active region 114 n and the sixth active region 116 n are also arranged along the second direction D2. The unit cell 110 u″ further includes a plurality of first gate structures 120 and a plurality of second gate structure 122. Both of the first gate structures 120 and the second gate structures 122 are arranged along the second direction D2 and extended along a first direction D1 perpendicular to the second direction D2 within a substrate-horizontal plane. In the preferred embodiment of the present invention, the unit cell 110 u″ can further include at least a dummy gate structure 120 d disposed between one first gate structure 120 and one second gate structure 122, and the dummy gate structure 120 d is also extended along the second direction D2. As shown in FIG. 9, the first gate structures 120 straddle the first active region 112 p and the second active region 112 n, and also straddle the third active region 114 p and the fourth active region 114 n while the second gate structures 122 straddle the fifth active region 116 p and the sixth active region 116 n. The unit cell 110 u″ further includes a plurality of first conductive structures 130. As shown in FIG. 9, the first conductive structures 130 are disposed on the first active region 112 p, the second active region 112 n, the third active region 114 p, the fourth active region 114 n, the fifth active region 116 p, the sixth active region 116 n, and two opposite ends of the first gate structures 120 and the second gate structures 122. According to the preferred embodiment, each of the unit cells 110 u″ further includes a plurality of second conductive structures 132 extending along the first direction D1 and the straddling the first active region 112 p and the second active region 112 n. The second conductive structures 132 also straddle the third active region 114 p and the fourth active region 114 n, and straddle the fifth active region 116 p and the sixth active region 116 n. As shown in FIG. 9, portions of the first conductive structures 130 are disposed on the second conductive structures 132 in the substrate-thickness plane.

As mentioned above, the constructing elements of the unit cells 110 u″, such as the first gate structures 120, the second gate structures 122, the first conductive structures 130 and the second conductive structures 132, can be formed by the same steps performed to the chip areas 104. In other words, the first gate structures 120 and the second gate structures 122 can be formed simultaneously with forming the gate structures (not shown) in the chip areas 104. In the same concept, the second conductive structures 132 can be formed simultaneously with forming contact and/or slot contact (not shown) in the chip areas 104, and the first conductive structures 130 can be formed simultaneously with forming via structures (not shown) in the chip areas 104. Therefore, the pattern densities in the scribe line 106 and the chip areas 104 are similar.

Please refer to FIG. 10, which is a schematic drawing illustrating a modification to the third preferred embodiment provided by the present invention. According to the modification, each of the unit cells 110 u″ further includes a pair of first wiring layers 140 extending along the second direction D2. And the pair of first wiring layers 140 are respectively formed at the two opposite ends of the first gate structures 120 and the second gate structures 122. According to the modification, the first wiring layers 140 on the same side in one single unit cell 110 u″ are spaced apart from each other, and the first wiring layers 140 on the same side in different unit cells 110 u″ arranged in a same row are spaced apart from each other as shown in FIG. 10, but not limited to this. As mentioned above, the pair of the first wiring layers 140 can be formed simultaneously with forming a wiring layer (not shown), such as a first metal wiring layer (M1) of an interconnection structure (not shown) in the chip areas 104. Therefore, the wiring pattern densities in the scribe line 106 and the chip areas 104 are similar.

Please refer to FIG. 11, which is a schematic drawing illustrating another modification to the third preferred embodiment provided by the present invention. According to the modification, each of the unit cells 110 u″ further includes a plurality of second wiring layers 142 extending along the second direction D2. According to the modification, the second wiring layers 142 in different unit cells 110 u″ in the same row are connected to each other as shown in FIG. 11. However, those skilled in art would easily realize that the second wiring layers 142 in different unit cells 110 u″ in the same row can be physically spaced apart from each other if required. As mentioned above, the second wiring layers 140 can be formed simultaneously with forming a wiring layer (not shown), such as a second metal wiring layer (M2) of the interconnection structure (not shown) in the chip areas 104. Therefore, the wiring pattern densities in the scribe line 106 and the chip areas 104 are similar.

According to the semiconductor device 100 provided by the present invention, the mark pattern 110 formed in the scribe line 106 is constructed by the plurality of unit cells 110 u″, and each unit cell 110 u″ includes configurations identical to the devices such as inverter(s) formed in core region(s) and pMOS/nMOS formed in I/O region(s) in the chip areas 104. Therefore, pattern densities in the scribe line 106 and the chip areas 104 are made the same, and thus loading effect is mitigated. Furthermore, since the unit cells respectively include elements formed in different layers such as the layer of the first gate structures 110 and the second gate structures 112, the layer of the second conductive structures 132, the layer of the first conductive structures 130, the layer of the first wiring layers 140, and the layer of the second wiring layers 142, it is concluded that at least those layers are involved for constructing the unit cells 110 u″. Thus layer-to-layer integration is easily achieved.

According to the semiconductor devices provided by the present invention, the mark pattern formed in the scribe line is constructed by the plurality of unit cells, and each unit cells includes configurations identical to the devices formed in the chip areas. Therefore, pattern densities in the scribe line and the chip areas are made the same, and thus loading effect is mitigated. Secondly, since the unit cells are formed in the scribe line simultaneously with forming the devices formed in the chip areas, the size of the unit cells is adjustable, depending on what kind of devices are to be formed in the chip areas. Therefore, the mark pattern of the semiconductor device provided by the present invention includes a superior flexibility. Furthermore, since the unit cells respectively include elements formed in different layers, it is concluded that at least those layers are involved for constructing the unit cells. Thus layer-to-layer integration is easily achieved.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. 

What is claimed is:
 1. A mark pattern in a semiconductor device, comprising: a plurality of unit cells immediately adjacent to each other and arranged in a form of dot matrix to form a register mark or an identification code, wherein each unit cell has configuration identical to functional devices of pMOS and nMOS, and wherein each unit cell comprises: a first active region; a second active region isolated from the first active region, wherein a conductivity type of the first active region is complementary to a conductivity type of the second active region; a plurality of first gate structures extending along a first direction and arranged along a second direction perpendicular to the first direction, and the first gate structures straddling the first active region and the second active region; a plurality of contact structures disposed between the first gate structures on the first active region and the second active region; and a plurality of via structures disposed on the contact structures and two opposite ends of the first gate structures.
 2. The mark pattern in a semiconductor device according to claim 1, wherein each of the unit cells further comprises a pair of first wiring layers extending along the second direction, and respectively formed at the two opposite ends of the first gate structures.
 3. The mark pattern in a semiconductor device according to claim 2, wherein the first wiring layers of the unit cells in a same row are connected to each other.
 4. The mark pattern in a semiconductor device according to claim 2, wherein each of the unit cells further comprises a plurality of second wiring layers extending along the second direction.
 5. The mark pattern in a semiconductor device according to claim 4, wherein the second wiring layers of the unit cells in a same row are connected to each other.
 6. The mark pattern in a semiconductor device according to claim 1, wherein each of the unit cells further comprises a third active region and a fourth active region, the first active region and the third active region are arranged along the second direction, the second active region and the fourth active region are arranged along the second direction, and the first gate structures further straddling the third active region and the fourth active region.
 7. The mark pattern in a semiconductor device according to claim 6, wherein the first active region and the third active region comprise a first conductivity type, the second active region and the fourth active region comprise a second conductivity type, and the first conductivity type and the second conductivity type are complementary to each other.
 8. The mark pattern in a semiconductor device according to claim 7, wherein the first conductive structures are disposed in the third active region and the fourth active region.
 9. The mark pattern in a semiconductor device according to claim 7, wherein each of the unit cells further comprise a fifth active region comprising the first conductivity type and a sixth active region comprising the second conductivity type.
 10. The mark pattern in a semiconductor device according to claim 9, wherein the first active region, the third active region and the fifth active region are arranged along the second direction, and the second active region, the fourth active region and the sixth active region are arranged along the second direction.
 11. The mark pattern in a semiconductor device according to claim 9, wherein the first conductive structure are disposed in the third active region and the fourth active region, the fifth active region and the sixth active region.
 12. The mark pattern in a semiconductor device according to claim 9, wherein each of the unit cells further comprises a plurality of second gate structures straddling the fifth active region and the sixth active region.
 13. The mark pattern in a semiconductor device according to claim 12, wherein each of the unit cells further comprising a plurality of first wiring layers respectively formed at two opposite ends of the first gate structures and the second gate structures.
 14. The mark pattern in a semiconductor device according to claim 9, wherein each of the unit cells further comprises a plurality of second wiring layers extending along the second direction.
 15. The mark pattern in a semiconductor device according to claim 14, wherein the second wiring layers of the unit cells in a same row are connected to each other. 